The Microsoft Surface Pro 6 2018 carries a IPS LCD (PixelSense) display of 12.3″. The replacement part is specific to that panel, which is why the price you see is for this exact model and not an average.
A Microsoft Surface Pro 6 2018 Screen Replacement starts at $72.99 at verified shops in Miami, FL. The final price depends on your exact model — you see it before you commit.
Yes — every shop is verified and you see its warranty terms before booking.